<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

        .box{
            width: 300px;
            height: 300px;
            margin: 200px auto;
            border-radius: 50%;
            background: conic-gradient(red, magenta, blue, aqua, lime, yellow, red); 
        }
    </style>
</head>
<body>
    <div class="box">

    </div>
</body>
</html>